Implemented Array.prototype.lastIndexOf().

JerryScript-DCO-1.0-Signed-off-by: Dániel Bátyai [email protected]

Author: dbatyai

jerry-core/ecma/builtin-objects/ecma-builtin-array-prototype.cpp

@@ -529,6 +529,140 @@ ecma_builtin_array_prototype_object_index_of (ecma_value_t this_arg, /**< this a
   return ret_value;
 } /* ecma_builtin_array_prototype_object_index_of */
 
+/**
+ * The Array.prototype object's 'lastIndexOf' routine
+ *
+ * See also:
+ *          ECMA-262 v5, 15.4.4.15
+ *
+ * @return completion value
+ *         Returned value must be freed with ecma_free_completion_value.
+ */
+static ecma_completion_value_t
+ecma_builtin_array_prototype_object_last_index_of (ecma_value_t this_arg, /**< this argument */
+                                                   ecma_value_t arg1, /**< searchElement */
+                                                   ecma_value_t arg2) /**< fromIndex */
+{
+  ecma_completion_value_t ret_value = ecma_make_empty_completion_value ();
+
+  /* 1. */
+  ECMA_TRY_CATCH (obj_this,
+                  ecma_op_to_object (this_arg),
+                  ret_value);
+
+  ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);
+  ecma_string_t *magic_string_length_p = ecma_get_magic_string (ECMA_MAGIC_STRING_LENGTH);
+
+  /* 2. */
+  ECMA_TRY_CATCH (len_value,
+                  ecma_op_object_get (obj_p, magic_string_length_p),
+                  ret_value);
+
+  ECMA_OP_TO_NUMBER_TRY_CATCH (len_number, len_value, ret_value);
+
+  /* 3. */
+  uint32_t len = ecma_number_to_uint32 (len_number);
+
+  ecma_number_t* num_p = ecma_alloc_number ();
+  *num_p = ecma_int32_to_number (-1);
+
+  /* 4. */
+  if (len == 0)
+  {
+    ret_value = ecma_make_normal_completion_value (ecma_make_number_value (num_p));
+  }
+  else
+  {
+    uint32_t k = len - 1;
+
+    /* 5. */
+    if (!ecma_is_value_undefined (arg2))
+    {
+      ECMA_OP_TO_NUMBER_TRY_CATCH (arg_from_idx, arg2, ret_value);
+      int32_t n = ecma_number_to_int32 (arg_from_idx);
+
+      /* 6. */
+      if (n >= 0)
+      {
+        /* min(n, len - 1)*/
+        if ((uint32_t) n > len - 1)
+        {
+          k = len - 1;
+        }
+        else
+        {
+          k = (uint32_t) n;
+        }
+      }
+      /* 7. */
+      else
+      {
+        n = -n;
+
+        /* We prevent k from being negative, so that we can use an uint32 */
+        if ((uint32_t) n <= len)
+        {
+          k = len - (uint32_t) n;
+        }
+        else
+        {
+          /*
+           * If k would be negative, we set it to UINT_MAX. See reasoning for this in the comment
+           * at the for loop below.
+           */
+          k = (uint32_t) -1;
+        }
+      }
+
+      ECMA_OP_TO_NUMBER_FINALIZE (arg_from_idx);
+    }
+
+    /* 8.
+     * We should break from the loop when k < 0. We can still use an uint32_t for k, and check
+     * for an underflow instead. This is safe, because k will always start in [0, len - 1],
+     * and len is in [0, UINT_MAX], so k >= len means we've had an underflow, and should stop.
+     */
+    for (;k < len && *num_p < 0 && ecma_is_completion_value_empty (ret_value); k--)
+    {
+      /* 8.a */
+      ecma_string_t *idx_str_p = ecma_new_ecma_string_from_uint32 (k);
+
+      /* 8.a */
+      if (ecma_op_object_get_property (obj_p, idx_str_p) != NULL)
+      {
+        /* 8.b.i */
+        ECMA_TRY_CATCH (get_value, ecma_op_object_get (obj_p, idx_str_p), ret_value);
+
+        /* 8.b.ii */
+        if (ecma_op_strict_equality_compare (arg1, get_value))
+        {
+          *num_p = ecma_uint32_to_number (k);
+        }
+
+        ECMA_FINALIZE (get_value);
+      }
+
+      ecma_deref_ecma_string (idx_str_p);
+    }
+
+    if (ecma_is_completion_value_empty (ret_value))
+    {
+      ret_value = ecma_make_normal_completion_value (ecma_make_number_value (num_p));
+    }
+    else
+    {
+      ecma_dealloc_number (num_p);
+    }
+  }
+
+  ECMA_OP_TO_NUMBER_FINALIZE (len_number);
+  ECMA_FINALIZE (len_value);
+  ecma_deref_ecma_string (magic_string_length_p);
+  ECMA_FINALIZE (obj_this);
+
+  return ret_value;
+} /* ecma_builtin_array_prototype_object_last_index_of */
+
 /**
  * The Array.prototype object's 'shift' routine
  *

jerry-core/ecma/builtin-objects/ecma-builtin-array-prototype.inc.h

@@ -63,6 +63,7 @@ ROUTINE (ECMA_MAGIC_STRING_TO_STRING_UL, ecma_builtin_array_prototype_object_to_
 ROUTINE (ECMA_MAGIC_STRING_POP, ecma_builtin_array_prototype_object_pop, 0, 0)
 ROUTINE (ECMA_MAGIC_STRING_PUSH, ecma_builtin_array_prototype_object_push, NON_FIXED, 1)
 ROUTINE (ECMA_MAGIC_STRING_INDEX_OF_UL, ecma_builtin_array_prototype_object_index_of, 2, 1)
+ROUTINE (ECMA_MAGIC_STRING_LAST_INDEX_OF_UL, ecma_builtin_array_prototype_object_last_index_of, 2, 1)
 ROUTINE (ECMA_MAGIC_STRING_SHIFT, ecma_builtin_array_prototype_object_shift, 0, 0)
 ROUTINE (ECMA_MAGIC_STRING_UNSHIFT, ecma_builtin_array_prototype_object_unshift, NON_FIXED, 1)
 ROUTINE (ECMA_MAGIC_STRING_SLICE, ecma_builtin_array_prototype_object_slice, 2, 2)

tests/jerry/array_prototype_lastindexof.js

@@ -0,0 +1,62 @@
+// Copyright 2015 Samsung Electronics Co., Ltd.
+// Copyright 2015 University of Szeged.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+var obj = {};
+var array = ["foo", 19, "bar", obj, "foo", 29, "baz"];
+
+var index = array.lastIndexOf("foo");
+assert(index === 4);
+assert(array[index] === "foo");
+
+assert(array.lastIndexOf("foo", 3) === 0);
+assert(array.lastIndexOf("foo", -8) === -1);
+
+var index = array.lastIndexOf("baz");
+assert(index === 6);
+assert(array[index] === "baz");
+
+assert(array.lastIndexOf("baz", -2) === -1);
+
+var index = array.lastIndexOf(obj);
+assert(index === 3);
+assert(array[index] === obj);
+
+var arr = [];
+arr[4294967294] = "foo";
+assert(arr.lastIndexOf("foo", -1) === 4294967294)
+
+// Checking behavior when unable to get length
+var obj = { lastIndexOf : Array.prototype.lastIndexOf}
+Object.defineProperty(obj, 'length', { 'get' : function () { throw new ReferenceError ("foo"); } });
+
+try {
+	obj.lastIndexOf("bar");
+	assert(false);
+} catch (e) {
+	assert(e.message === "foo");
+	assert(e instanceof ReferenceError);
+}
+
+// Checking behavior when unable to get element
+var obj = { lastIndexOf : Array.prototype.lastIndexOf, length : 1}
+Object.defineProperty(obj, '0', { 'get' : function () { throw new ReferenceError ("foo"); } });
+
+try {
+	obj.lastIndexOf("bar");
+	assert(false);
+} catch (e) {
+	assert(e.message === "foo");
+	assert(e instanceof ReferenceError);
+}